Stepped rear strap for bottom feed separators

ABSTRACT

A rear stop for a device for feeding sheets one at a time from a stack of sheets with the feeding device comprising a frame supporting a front gauge, front and rear stack supports and the rear stop, means for shifting the leading edges of each of the sheets against the front gauge and means reciprocated between a pair of positions for feeding the lowermost sheet of a stack beneath the front gauge characterized by the rear stop being mounted for vertical movement in the frame and the stop having a plurality of abutment surfaces disposed at different levels so the rear stop has a stair step cross-sectional configuration. A preferred embodiment of the rear stop is formed by a stack of plates which are arranged to form the stair step configuration. In order to provide different spacing between the abutments, the thicknesses of the plates of the stack may be different.

United States Patent Salvade Nov. 4, 1975 [75] Inventor: Gennaro Salvade, Pieeraz-Mur E.,

Switzerland [73] Assignee: J. Bobst & Fils S.A., Switzerland [22] Filed: May 9, 1974 [21] Appl. No.: 468,390

[30] Foreign Application Priority Data June 21, 1973 Switzerland 9189/73 [52] US. Cl. 271/133; 271/165 [51] Int. Cl. B65H l/06 [58] Field of Search 271/133, 134, 135, 144,

[56] References Cited UNITED STATES PATENTS 1,281,014 10/1918 Huneke 271/135 2,902,280 9/1959 Shields.... 271/134 3,715,116 2/1973 Salvade 271/165 Primary ExaminerRichard A. Schacher Assistant Examiner-Bruce H. Stoner, Jr. Attorney, Agent, or Firm-Hill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson [57] ABSTRACT A rear stop for a device for feeding sheets one at a time from a stack of sheets with the feeding device comprising a frame supporting a front gauge, front and rear stack supports and the rear stop, means for shifting the leading edges of each of the sheets against the front gauge and means reciprocated between a pair of positions for feeding the lowermost sheet of a stack beneath the front gauge characterized by the rear stop being mounted for vertical movement in the frame and the stop having a plurality of abutment surfaces disposed at different levels so the rear stop has a stair step cross-sectional configuration. A preferred embodiment of the rear stop is formed by a stack of plates which are arranged to form the stair step configuration. In order to provide different spacing between the abutments, the thicknesses of the plates of the stack may be different.

9'Claims, 4 Drawing Figures Sheet 1 of 2 US. Patent Nov. 4, 1975 US. Patent NOV.4, 1975 Sheet20f2 3,917,259

m a I STEPPED REAR STRAP FOR BOTTOM FEED SEPARATORS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is concerned with a sheet stopping device which is located in a feeding device for corrugated or solid board sheets. The feeding device includes a front gauge which coacts with the stop and other structure to form a means for receiving a stack of sheets and a reciprocating feeding head for feeding the lowermost sheet of a stack beneath the front gauge.

2. The Prior Art When feeding a corrugated board or solid board sheet, several problems can occur. For example, for correct feeding, it is desired that the leading edge portion of the sheet lie substantially flat on a front guide or support of the feeding device so that the sheet may be fed from the device. If the sheet has a curvature, the leading edge portion may not lie flat on the front guide or support. To correct for curvature of the sheet, the feeding device is provided with sensing means to determine if the leading edge is lying flat on the support 'and the sensing means will raise or lower the rear sheet supports until the leading edge portion is flat on the front support. This type of feeding device is disclosed in US. Pat. No. 3,7l5,l 16 (which corresponds to Swiss Pat. No. 524,528).

Another problem that occurs when feeding a sheet one at a time from a stack of sheets is that each of the sheets in the stack may have a different length. In order to have the desired registry of the sheet when introduced into a processing device, it is desirable to have all the leading edges engaging a front gauge. To shift each of the sheets so that their leading edges are engaging the front gauge or abutment, it has been suggested to use a rear shuttle which has a plurality of flat sheets or pins for engaging the rear edge of each of the sheets. The pins or fiat sheets are resiliently carried in the shuttle which is reciprocated from a withdrawn position which allows downward movement of the sheet to a position of engagement with the stack to shift all of the sheets againstthe front gauge or stop. If registry of the side edges of the sheets in a stack is desired, a similar shuttle can be used to shift all of the sheets against a side guide. An example of the above-described apparatus is disclosed in US. Pat. No. 3,711,088 (which corresponds to Swiss Pat. No. 524,530).

As mentioned above, in order to ensure proper registry of each sheet in a stack with a conveying device of the machine processing the sheet, it is essential that the leading edge of each sheet engages the front gauge.

During a return stroke of the feeding device, such as the suction head, from its forward position to a position which is beneath the lowermost sheet of the stack, frictional engagement of the head with the next lowermost sheet on the return stroke will cause a shifting of the sheet away from the front gauge unless it is prevented by a rear stop. When the sheets of the stack have different lengths, the rear stop must be set to accommodate the largest or longest sheet of the stack. Thus, when a shorter sheet is the lowermost sheet, it will be moved from its position of alignment with the front gauge until rearward movement of the sheet is prevented by engagement of the rear edge with the rear stop. Thus, it is almost impossible when feeding sheets from a stack of sheets of different lengths to insure an exact, accurate 2 registry of each sheet with regard to the conveying appliance of the machine which is subsequently processing the sheets.

SUMMARY OF THE INVENTION The present invention is directed to a device which insures accurate registry for each sheet of a stack as it is being fed from a feeding device and is introduced into a processing machine. To accomplish this task, the feeding device comprises a frame supporting a front gauge, front and rear stack supports and a rear stop to define means to receive a stack of sheets, means for shifting a leading edge of each of the sheets against the front gauge, and means reciprocated between a pair of positions for feeding the lowermost sheet of the stack beneath the front gauge with the improvements comprising means for mounting the rear stop in the frame for vertical movement relative to the front gauge and the rear stop having a plurality of spaced abutment surfaces each disposed at different levels to provide the rear stop with a stair step cross-sectional configuration so that during a return stroke of the feeding means a rear edge of the lowermost sheet of the stack is engaged on one of the abutment surfaces which prevents shifting of the lowermost sheet from its aligned position relative to the front gauge. Preferably, the stair step crosssectional configuration is formed by a plurality of sheets or plates arranged in a stack and the plates preferably have different thicknesses so that the distance between adjacent stops is varied.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a sheet feeding unit or device equipped with a stopping device according to the present invention;

FIG. 2 is a view taken along II-II of FIG. 1;

FIG. 3 is an enlarged front view of the rear stop of the present invention; and

FIG. 4 is a cross-sectional view taken along lines IV-IV of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The principles of the present invention are particularly useful in a sheet feeding device for delivering a sheet 1 from a stack 2 one at a time into a gripper 3 of a conveying device 4 of a machine which perfonns subsequent operations on the sheet.

The feeding device has a frame which supports a rear stop 7, a front gauge 10, a pair of spaced front supports or guides 11 and a pair of side guides 11. The device further includes means for feeding the lowermost sheet beneath the front gauge 10 into the gripper 3 which means is illustrated as a suction head 5 carried by means generally indicated by a box 5 for reciprocating it from a forward position illustrated in bold lines to a withdrawn position whichis beneath the stack 2 and is illustrated in chain lines adjacent the front supports 1 l.

The stack 2 is composed of a plurality of sheets which have different lengths or dimensions. To ensure that the leading edge of each of the sheets of the stack 2 is in engagement with the front gauge l0,'the feeding device includes means for shifting each sheet which means is illustrated as a pair of rotating brushes8 (FIG. 2) that'en gage the trailing edge of each sheet and which brushes are carried on shafts extending from a pair of motors 9 which are mounted on the frame of the device by appropriate structure.

As illustrated in FIG. 1, as the sheet 1 is fed to the gripper 3, the next lower sheet 6 is received on the stop 7 and is also supported by a pair of spaced arms or supports 12 and 13 (FIG. 2). The arms 12 and 13 are carried by a shaft 14 which extends between the pair of frame members 15 and 16 of the device.

As best illustrated in FIGS. 3 and 4, the rear stop 7 is formed by a support member 22 which is provided with a pair of rollers 24 on each end. Each roller 24 is mounted by a bearing on screw 23 which attaches the roller to the support 22. To form a plurality of abutment surfaces, a stack of individual plates or sheets 30 are held on the support 22 by screws 27, 28 and 29. The screws 27 and 29 also hold support blocks 31. Each of the plates or sheets 30 (FIG. 4) extend in a vertical plane and has a different width so that each plate has an exposed surface portion adjacent its upper edge to form an abutment surface with each abutment surface being at a different level to provide a stairstep configuration for the rear stop 7. Each of the plates or sheets 30 can have different thicknesses so that the distance between adjacent abutment surfaces is varied.

The stop 7 is mounted on the frame for vertical movement relative to the front gauge 10. The means for mounting the stop comprises a pair of upstanding frame members 17 and 18 which have grooves 25 and 26 which form slides for receiving the rolls 24 on the ends of the support member 22. The front support blocks 31 of the stop 7 ride on rollers carried on arms 19 and 20 which arms are adjustably connected to the shaft 14. A rotation of the shaft 14 will raise and lower the stop 7 in the slides relative to the front gauge 10.

As illustrated in FIG. 1, a table or plate 21 extends across the top of the upstanding frame members 17 and 18. The table 21 provides a flat surface which facilitates loading the means for receiving the stack 2.

- In operation, as the suction head or plate carries the sheet 1 into the gripper 3, the next lower sheet6 is engaged on one of the plates 30 with its trailing end abuting one of the abutment surfaces. After removal of the sheet 1 by the gripper 3 and during the return.

stroke of the feed head 5, friction of the feed head 5 on the sheet 6 will not shift the sheet away from the guide or gauge due to the engagement of the trailing edge of the sheet with one of the abutment surface. As mentioned, the position of the rear stop 7 can be shifted vertically so that the lowermost sheet such as 6 is in the desired position for a subsequent feeding operation. The vertical shifting of the stop 7 is accomplished by rotation of the shaft 14. If it is desired to automatically shift the vertical position of the stop 7 to maintain the sheets flat on the guide 11, the rotation of the shaft 14 can be accomplished by an electric motor which is controlled by sensing means located adjacent the front guide or support 1 1. A detailed description of the sensing means and control circuit for a motor to rotate the shaft is given in the above-mentioned U.S. Pat. No. 3,715,116 and this description is hereby incorporated by reference thereto.

The rear stop 7 with a plurality of spaced abutment surfaces prevents shifting of the sheet such as 6 away from its alignment with the front gauge during the return stroke of the suction head 5. Thus, the rear stop 7 insures the accurate registry of each sheet of the stack 2 as it is being fed from the device. In addition, the low profile of the stop facilities loading additional sheets into the stack 2 of the feeding device.

Although various minor modifications may be sug-,

gested' by those versed in the art, it should be understood that I wish to employ within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the art.

I claim:

1. In a device for feeding sheets one at a time from a stack of sheets, the device comprising a frame supporting a front gauge, front and rear stack supports and a rear stop to define means for receiving a stack of sheets, means for shifting a leading edge of each of the sheets against the front gauge and means reciprocated between a pair of positions for feeding the lowermost sheet of the stack beneath the front gauge, the improvements comprising said rear stop having a plurality of spaced abutment surfaces, each disposed at different levels to provide the rear stop with a stair step crosssectional configuration, and means for mounting said rear stop in the frame for vertical movement relative to the front gauge with the abutment surfaces moving in substantially vertical planes so that during a return stroke of the feeding means, a rear edge of the lowermost sheet of the stack is engaged on one of. the abutment surfaces which prevents shifting of the lowermost sheet from its aligned position relative to the front gauge.

2. In a device according to claim 1, wherein .the rear stop is formed by a stack of plates which are arranged with their edges forming the stair step configuration.

3. In a device according to claim 2, wherein each of the plates has a different width.

4. In a device for feeding sheets one at a time from .a

stack of sheets, the device comprising a frame supporting a front gauge, front and rear stack supports and a rear stop to define means for receiving a stack of sheets, means for shifting a leading edge of each of the sheets against the front gauge and means reciprocated between a pair of positions for feeding the lowermost sheet of the stack beneath the front gauge, the improvements comprising means for mounting said rear stop in the frame for vertical movement relative to the front gauge and said rear stop being a stack of plates with each plate of the stack being disposed in a vertical 1 plane and having an upper edge extending to a different level'to expose a portion of the surface adjacent the upper edge of the next adjacent plate to provide a plurality of spaced abutment surfaces each disposed at different levels to provide the rear stop with a stair step cross-sectional configuration so that during a return stroke of the feeding means, a rear edge of the lowermost sheet of the stack is engaged on one of the abutment surfaces which prevents shifting of the lowermost sheet from its aligned position relative to the front gauge.

5. In a device according to claim 4, wherein each of the'plates has a difierent thickness so that the spacing between adjacent abutments is different.

6. In a device for feeding sheets one at a time froma stack of sheets, the device comprising a frame supporting a front gauge, front and rear stack supports and a rear stop to define means for receiving a stack of sheets, means for shifting a leading edge of each of the sheets against the front gauge and means reciprocated between a pair of positions for feeding the lowermost sheet of the stack beneath the front gauge, the improvements comprising means for mounting said rear stop in. the frame for vertical movement relative to the 7. In a device according to claim 6, wherein the rear stop is formed by a stack of plates which are arranged with their edges forming the stair step configuration.

8. In a device according to claim 7, wherein each of the plates of the stacks is disposed in a vertical plane and each of the abutment surfaces is formed by a surface of the plate adjacent an edge thereof.

9. In a device according to claim 8, wherein each of the plates has a different thickness so that the spacing between adjacent abutment surfaces is different. 

1. In a device for feeding sheets one at a time from a stack of sheets, the device comprising a frame supporting a front gauge, front and rear stack supports and a rear stop to define means for receiving a stack of sheets, means for shifting a leading edge of each of the sheets against the front gauge and means reciprocated between a pair of positions for feeding the lowermost sheet of the stack beneath the front gauge, the improvements comprising said rear stop having a plurality of spaced abutment surfaces, each disposed at different levels to provide the rear stop with a stair step cross-sectional configuration, and means for mounting said rear stop in the frame for vertical movement relative to the front gauge with the abutment surfaces moving in substantially vertical planes so that during a return stroke of the feeding means, a rear edge of the lowermost sheet of the stack is engaged on one of the abutment surfaces which prevents shifting of the lowermost sheet from its aligned position relative to the front gauge.
 2. In a device according to claim 1, wherein the rear stop is formed by a stack of plates which are arranged with their edges forming the stair step configuration.
 3. In a device according to claim 2, wherein each of the plates has a different width.
 4. In a device for feeding sheets one at a time from a stack of sheets, the device comprising a frame supporting a front gauge, front and rear stack supports and a rear stop to define means for receiving a stack of sheets, means for shifting a leading edge of each of the sheets against the front gauge and means reciprocated between a pair of positions for feeding the lowermost sheet of the stack beneath the front gauge, the improvements comprising means for mounting said rear stop in the frame for vertical movement relative to the front gauge and said rear stop being a stack of plates with each plate of the stack being disposed in a vertical plane and having an upper edge extending to a different level to expose a portion of the surface adjacent the upper edge of the next adjacent plate to provide a plurality of spaced abutment surfaces each disposed at different levels to provide the rear stop with a stair step cross-sectional configuration so that during a return stroke of the feeding means, a rear edge of the lowermost sheet of the stack is engaged on one of the abutment surfaces which prevents shifting of the lowermost sheet from its aligned position relative to the front gauge.
 5. In a device according to claim 4, wherein each of the plates has a different thickness so that the spacing between adjacent abutments is different.
 6. In a device for feeding sheets one at a time from a stack of sheets, the device comprising a frame supporting a front gauge, front and rear stack supports and a rear stop to define means for receiving a stack of sheets, means for shifting a leading edge of each of the sheets against the front gauge and means reciprocated between a pair of positions for feeding the lowermost sheet of the stack beneath the front gauge, the improvements comprising means for mounting said rear stop in the frame for vertical movement relative to the front gauge, said means for mounting including a pair of spaced slides disposed on the frame receiving opposite ends of the stop, and said rear stop having a plurality of spaced abutment surfaces, each disposed at different levels to provide the rear stop with a stair step cross-sectional configuration so that during a return stroke of the feeding means, a rear edge of the lowermost sheet of the stack is engaged on one of the abutment surfaces which prevents shifting of the lowermost sheet from its aligned position relative to the front gauge.
 7. In a device according to claim 6, wherein the rear stop is formed by a stack of plates which are arranged with their edges forming the stair step configuration.
 8. In a devicE according to claim 7, wherein each of the plates of the stacks is disposed in a vertical plane and each of the abutment surfaces is formed by a surface of the plate adjacent an edge thereof.
 9. In a device according to claim 8, wherein each of the plates has a different thickness so that the spacing between adjacent abutment surfaces is different. 